Regarding Vintage RayBans

From 1937 to 1998 Ray Bans were made by an optics company called Bausch and Lomb in USA and France, hence the 'BL' engraving on vintage lenses. The 'Ray Ban' logo printed on the lens only appeared on later models from the 80's onwards, earlier examples with no lens logo printed are still genuine - From 1998 to present day Ray Bans have been made by a company called Luxottica in Italy, lenses inscribed with 'RB'

Ray Ban Manufacturer

Ray-Ban is a manufacturer of sunglasses, founded in 1937 by Bausch & Lomb. They were introduced for the United States Army Air Corps. In 1999, Bausch & Lomb sold the brand to the Italian Luxottica Group for a reported 1.2 billion dollars. Ray-Bans were initially created in 1937. Some years ealier, Lieutenant John MacCready had returned from a balloon flying adventure and complained that the sun had done permanent damage to his eyes. He contacted Bausch & Lomb asking them to create a type of sunglasses that would not only provide superb protection, but also look elegant. On May 7, 1937, Bausch & Lomb officially took out the patent. The prototype, known as Anti-Glare, consisted of an extremely light frame weighing 150 grams. They were made of gold-plated metal with two green lenses made of mineral glass to filter out infrared and ultraviolet rays. Pilots in the United States Army Air Corps immediately adopted the sunglasses. The Ray-Ban Aviator became a well-known style of sunglasses when General Douglas MacArthur landed on the beach in the Philippines in World War II, and photographers snapped several pictures of him wearing them.